This invention relates to a method and system for bypassing Media Gateways in wireless networks. While the invention is particularly directed to the art of telecommunications, and will be thus described with specific reference thereto, it will be appreciated that the invention may have usefulness in other fields and applications.
By way of background, wireless telecommunication networks, which are well known, allow mobile devices to communicate with each other and other networks, such as the Internet and the Public Switched Telephone Network (PSTN).
In general, the Universal Mobile Telecommunication System (UMTS) is a third generation mobile communications system that has evolved from the Global System for Mobile communication (GSM). The UMTS is intended to provide various mobile communication services by combining a UMTS Terrestrial Radio Access Network (UTRAN) with a Circuit-Switched (CS) Core Network (CN) based on the GSM.
The specification of the UMTS is currently being developed by a standardization group called the Third Generation Partnership Project (3GPP). In the 3GPP specifications, a Mobile Switching Center/Visitor Location Resister (MSC/VLR), which is a core network node belonging to a circuit switched region, is divided into Mobile Switching Center (MSC) servers and Media Gateways (MGWs).
In particular, the 3GPP is currently developing new worldwide standards for the creation, delivery, and playback of multimedia over new, high-speed wireless networks. These standards will enable the free sharing of multimedia between a variety of devices, including cell phones, Personal Digital Assistants (PDAs), and notebook and desktop computers. 3GPP devices include, in addition to a voice communication interface, capability for communication of data and display of data, including video.
3GPP specifications mandate the use of a Media Gateway (MGW) in the bearer path for voice calls and Circuit Switched Data (CSD) calls in the circuit core network. The MGW receives packetized voice from the Radio Network Controller (RNC) via Iu User Plane Protocol (IuUP) framing. Packetized voice is the process of converting audio signals into digital packet format, transferring these packets through a packet network, reassembling these packets into their original data form, and then recreating the audio signals. The voice or CSD packets then traverse through the MGW on route toward the destination. It is existing art (and in the process of standardization in 3GPP) to use IETF standard protocols to carry voice and data between MGWs in the core network. In many cases, the MGW does nothing more than convert the type of packetization used for the voice and data, i.e., converting between IuUP framing and IETF framing formats, where no transcoding of voice to another format is necessary. The newly reframed packets are then sent on toward the destination, which can be another MGW, a RNC, an IP Multimedia Subsystem (IMS), and so on. Using a MGW solely for performing a reframing function is not efficient from a cost and voice quality perspective.
Accordingly, the present invention contemplates a new and improved method and system that resolves the above-referenced difficulties and others. More particularly, this invention devises a method and system for eliminating MGWs from the bearer path when they are not needed. This invention is only applicable to an MSC when originating or terminating a call for a wireless subscriber. The prior art describes means of bypassing MGWs at transit exchanges and handover anchors, but does not describe the case of MGW bypass when the MSC is controlling access to a subscriber device via a RAN. This invention achieves at least two purposes for network providers: reducing cost by using less equipment in the network and improving voice quality by reducing bearer delay.